Dedicated specificity comparator in PathPattern

The PathPattern compareTo method is now consistent with equals when
two patterns are of the same specificity but otherwise different.

Separately PathPattern now exposes a Comparator by specificity that
offers the current functionality of compareTo. This can be used for
actual sorting where we only care about specificity.

spring-web/src/test/java/org/springframework/web/util/pattern/PathPatternParserTests.java

@@ -387,7 +387,7 @@ public class PathPatternParserTests {
 		// Based purely on catchAll
 		p1 = parse("{*foobar}");
 		p2 = parse("{*goo}");
-		assertEquals(0, p1.compareTo(p2));
+		assertTrue(p1.compareTo(p2) != 0);
 
 		p1 = parse("/{*foobar}");
 		p2 = parse("/abc/{*ww}");